Habibe Genc

Protein oxidation markers in women with and without gestational diabetes mellitus: a possible relation with paraoxonase activity.

AIMS To clarify the levels of protein oxidation markers such as protein carbonyl (PCO), protein hydroperoxides (P-OOH), advanced oxidation protein products (AOPP) and nitrotyrosine (NT), as well as antioxidative enzymes such as paraoxonase (PON-1) in women with and without gestational diabetes mellitus (GDM). METHODS The study was conducted on 23 women with GDM and 22 women without GDM. The levels of the P-OOH, AOPP, and PON-1 were determined by colorimetric methods; whereas NT and PCO levels were measured by ELISA. RESULTS The concentrations of protein oxidation markers were significantly increased and PON1 activity was significantly decreased in GDM group compared to those of normal pregnant women. The control group showed a significant negative correlation between PON-1 and PCO (r=-0.451, p=0.027); whereas in GDM group, there was a significant positive correlation between P-OOH and HbA1c (r=0.89, p=0.001). There was no significant correlation between AOPP, PON-1, P-OOH, PCO, and HbA1c in either group. CONCLUSIONS There is evidence of a possible association between protein oxidation and decreased PON1 activity in GDM. The increase in protein oxidation parameters in the GDM group leading to decreased PON1 activity might, we think, create a predisposition for clinical complications in GDM group.

Gender difference as regards myocardial protein oxidation in aged rats: male rats have increased oxidative protein damage

Objective The reasons for the difference in life expectancy between males and females are still unknown. Previous studies have provided compelling evidence for the presence of oxidized proteins, and lipids in advanced human atherosclerotic lesions. The gender factor responsible for such protein oxidation is unknown and controversial. Our aim was to reveal the difference between myocardial protein and lipid oxidation parameters of male and female aged rats. Methods We investigated the relation between myocardial protein carbonyl (PCO) and other protein oxidation parameters such as advanced oxidation protein products (AOPP), nitrotyrosine (NT), protein hydroperoxide (P-OOH), and protein thiol (P-SH). Our study also covered other oxidative stress parameters, such as total thiol (T-SH), non-protein thiol (Np-SH), 4-hydroxyalkenal (4-HAE), malondialdehyde (MDA), reduced glutathione (GSH), and the glutathione disulfide (GSSG). Results Among the studied parameters, myocardial PCO, AOPP, NT, Np-SH, GSH, Fe2+ levels and the redox index (RI) of male rats were significantly higher than in the female group. On the other hand, P-OOH, P-SH, T-SH, 4-HAE, and MDA levels were all found to be not different. Conclusions These data support the hypothesis that elevated levels of PCO, AOPP, and NT contribute to the extent of protein, but not lipid, oxidation in aged male rats. We are of the conviction that the increased myocardial Np-SH, GSH and RI levels that we have determined in aged male rats may be a protective factor in propagation of protein oxidation. Our findings support our conviction that protein and lipid oxidation, in the myocardial tissue of aged rats, have a controlling role in differing regulating mechanisms through gender differences.

Effect of vitamin C on oxidative liver injury due to isoniazid in rats

Background:  The aim of the present study was to investigate the effect of different doses of vitamin C on oxidative liver injury due to isoniazid (INH) in rats.

Ezetimibe therapy and its influence on oxidative stress and fibrinolytic activity.

Objective: The effect of ezetimibe on blood lipids, oxidative stress, and fibrinolytic activity in hyperlipidemic patients was investigated after three months of therapy. Methods: Thirty hyperlipidemic patients were treated for twelve weeks with ezetimibe 10 mg/day. A healthy control group with matching age and gender was also included. Fasting blood glucose, lipid parameters, paraoxonase (PON1), protein carbonyl (PCO), oxidized LDL (oxLDL), 8-isoprostane (ISOPR), total antioxidant capacity (TAC) levels, tissue-type plasminogen activator (tPA), plasminogen activator inhibitor type-1 (PAI-1), and PAI-1/t-PA levels were evaluated. Results: Ezetimibe therapy for twelve weeks led to changes in lipid profile in accordance with the literature. Fibrinolytic activity parameters, PAI-1/tPA and tPA-1 decreased, whereas PAI-1 levels did not change significantly. Antioxidant parameters, serum PON1 activity, and TAC levels increased significantly compared with the basal values. Oxidant parameters, oxLDL, ISOPR, and PCO (which is an indicator of oxidative protein damage) decreased significantly after therapy. Conclusions: Ezetimibe therapy has beneficial effects on fibrinolytic activity and homeostasis between oxidant and antioxidant activity in hyperlipidemic patients This may be through lowering lipid levels or other mechanisms such as decreasing insulin resistance and the pleiotropic effects of the drug.

Serum paraoxonase activity and oxidative DNA damage in patients with laryngeal squamous cell carcinoma.

Objectives: To determine the possible role of oxidants and antioxidants in the pathogenesis of in laryngeal squamous cell carcinoma. Design and Setting: Our study involved patients with newly diagnosed laryngeal cancer (n = 29) and same age- and sex-matched healthy individuals (n = 21). Serum malondialdehyde (MDA) and paraoxonase (PON1) levels were measured by colorimetric methods and 8-hydroxy-2&vprime;-deoxyguanosine (8-OH-dG) was measured using enzyme-linked immunosorbent assay in fasting blood samples of participants. Results: The levels of 8-OH-dG (control, 4.61 ± 1.27 ng/mL; patient, 11.70 ± 2.44 ng/mL; P < 0.001) and MDA (control, 4.16 ± 1.02 nmol/mL; patient, 8.74 ± 1.65 nmol/mL; P < 0.001) were significantly higher, and those of PON1 (control, 170.86 ± 72.46 U/mL; patient, 80.44 ± 29.81 U/mL; P < 0.001) were significantly lower in patients. There were no statistically significant differences in the 8-OH-dG, MDA levels, and PON1 activity in relation to T (tumor) staging of differentiation and different smoking/drinking status. There was a statistically significant difference in MDA levels (10.24 ± 0.64 nmol/mL) only in stage II laryngeal cancer. There were a statistically significant positive correlation between serum MDA and 8-OH-dG (r = 0.887, P < 0.001), a statistically significant negative correlation between serum MDA and serum PON1 (r = −0.477, P < 0.01), and a statistically significant negative correlation between serum 8-OH-dG and serum PON1 in patients (r = −0.420, P < 0.05). Conclusions: We conclude that, in patients with laryngeal squamous cell carcinoma, the oxidant/antioxidant balance was impaired in favor of lipid peroxidation and DNA damage.

Serum paraoxonase (a high-density lipoprotein-associated lipophilic antioxidant) activity and lipid profile in experimental acute pancreatitis.

Objective: This study was designed to determine the serum lipid profile and the activity of paraoxonase (PON1, the lipophilic antioxidant component of high-density lipoprotein [HDL]-cholesterol) in acute pancreatitis. Methods: Acute pancreatitis was induced by injection of ethyl alcohol into the common biliary duct. Oxidative stress marker (malonyldialdehyde), lipid profile, and PON1 activity were determined in the serum. Results: In the acute pancreatitis group, whereas the mean levels of total cholesterol, low-density lipoproteins, and malonyldialdehyde were significantly higher (P < 0.001 for each), HDL level and PON1 activity were found to be significantly lower (P < 0.001 for each). Conclusions: Our results suggest that an abnormal lipid profile and decreased PON1 activity may have a role in the pathogenesis of acute pancreatitis in which HDL-associated antioxidant defense is impaired.

Levels of paraoxonase, an index of antioxidant defense, in patients with active sarcoidosis

ABSTRACT Objective: Oxidative mechanisms are currently discussed as playing a crucial role in the genesis of inflammatory lung diseases. We aimed to evaluate the oxidant–antioxidant balance in the pathogenesis and activity of sarcoidosis and to search if the change in the level of PON can be taken as an activity marker. Methods: 26 active sarcoidosis subjects aged 41.3 ± 12.9 years, 37 inactive subjects aged 39.6 ± 11.7 years and 48 control subjects aged 48.9 ± 2.5 years were recruited in our study. Malondialdehyde (MDA), paraoxonase1 (PON1) and oxidized low density lipoprotein (oxLDL) levels in serum were analyzed by spectrophotometric, kinetic, and ELISA methods, respectively. Results: PON1 levels were significantly lower in the active disease state than both the inactive form and control groups. MDA levels were significantly higher in active sarcoidosis than both the inactive disease and control groups, and oxLDL levels were significantly higher in the active disease group than the inactive group and control group. The level of PON1 in the inactive disease group is not significantly different from the control group while the oxLDL and MDA levels of inactive group is significantly higher than the control group (p < 0.001). There was a negative correlation between the PON1 activities and MDA values in both active and inactive groups (p = 0.008). Conclusion: Oxidative stress increases in sarcoidosis might be due to both increase in lipid peroxidation and decrease in antioxidant status (PON1) and the relationship between oxidative status and the activation of the disease should be discussed by comparing the previously known activation criteria.

Darbepoetin Alpha Ameliorates Neuronal Damage in a Rat Model of Acute Ethanol Intoxication

ABSTRACT Objective: Acute ethanol intoxication has been shown to cause oxidative damage in many organ systems including the brain. Erythropoietin has antioxidant effects and prevents neuronal damage in the animal model of ischemic brain injury. In this study, we aimed to investigate the effects of darbepoetin alpha, an analog of erythropoietin with a longer half-life and higher in vivo activity, on ethanol-induced acute brain injury. Methods: Forty-eight Wistar albino rats were allocated to four groups. The first group received ethanol treatment (E), the second group was treated with ethanol and darbepoetin (ED), the third group received only saline treatment (S), and the fourth group received both saline and darbepoetin treatment (SD). Plasma S100-β and neuron-specific enolase (NSE) levels were measured. Histopathological evaluation of the brains was performed. Results: The plasma S100-β and NSE levels were significantly lower in group ED compared with group E. In group E, we have observed focal red-neuron formation at the granular layer of the dentate gyrus. We did not observe any histopathological changes in the other groups (ED, S, and SD). Conclusion: Our findings suggest that darbepoetin alpha has neuroprotective effect in acute ethanol intoxication, possibly through its antioxidant effect.

Oxidative stress parameters and inflammatory and immune mediators as markers of the severity of sepsis

INTRODUCTION Sepsis is a complex inflammatory syndrome with diverse etiology and wide spectrum of severity. The aim of this study was to investigate whether inflammatory mediators, in comparison with oxidative parameters, are associated with severity of sepsis. METHODOLOGY Plasma neopterin, adenosine deaminase (ADA), vascular cell adhesion molecule (VCAM), intracellular adhesion molecule (ICAM), interleukin (IL)-1, IL-6, and tumor necrosis factor alpha (TNF-α), as inflammatory mediators, and serum nitric oxide (NOx), nitrotyrosine (NT), oxidized LDL (oxLDL) levels, serum paraoxonase 1 (PON1) activity, and erythrocyte glutathione (GSH) levels as oxidative stress parameters of 12 patients with mild sepsis, 25 patients with severe sepsis, and 20 healthy control subjects were evaluated. NOx, GSH levels and PON1 activity were determined by colorimetric methods, whereas neopterin, VCAM, ICAM, IL-1, IL-6, TNF-α, NT, and oxLDL levels were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS All parameters in mild and severe sepsis were significantly different from those of healthy subjects, except ADA activities. Patients with severe sepsis exhibited higher IL-6, TNF-α, NT, and oxLDL levels than patients with mild sepsis. GSH (98%, 98%), oxLDL (98%, 98%), VCAM-1 (99%, 99%), and ICAM-1 (99%, 99%) have much more sensitivitiy and specificity in sepsis. CONCLUSIONS Our results suggest that the oxidative stress and inflammatory response in patients with sepsis were increased and that serum IL-6, TNF-α, NT, and oxLDL levels were correlated with the severity of sepsis. Therefore, increases in these parameters may contribute to the dysfunction or failure of one or more organs, or even death, in sepsis.

Kefir ve enteral beslenme ürünlerinin kolon anastomozu üzerine etkileri: Deneysel çalışma / The effects of kefir and enteral feeding products on colonic anastomosis: Experimental study

Objective: Kefir is rich and affective probiotic feeding material with evidence based medical effects. There are many studies about antimicrobial, scatrizant, anticancer effects of Kefir but there is not any study on anastomotic burst pressure and healing effects on intestinal wall around anastomosis in the postoperative period (8). In this study the efficacy of Kefir (AltA½nkA½lA½A§) and Ensure (Abbott) as enteral feeding products as colonic anastomotic healing has been investigated. Material and Methods: In this study 40 Wistar-albino female rats were used. Rats were divided into 4groups as sham group (Group A), anastomosis group (Group B), kefir after anastomosis group (Group C), and ensure after anastomosis group (Group D). Results: There was no significant difference between the hemoglobin, hematocrit, leukocyte and thrombocyte levels of the groups (p>0.05) whereas there was statistically significant difference between the total protein levels of the groups (p